<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, inital-scale=1.0">
    <link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.0.2/css/bootstrap.min.css" rel="stylesheet">
    <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
    <script src="https://cdn.bootcdn.net/ajax/libs/popper.js/2.9.2/cjs/popper.min.js"></script>
    <script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.0.2/js/bootstrap.js"></script>
    <title>Title</title>
</head>
<body>
<div class="container-fluid">
    <div class="row">
        <div class="col-xs-6 col-sm-6 col-md-6 col-lg-6 bg-success">
            <h3>第一行第一列</h3>
        </div>
        <div class="col-xs-6 col-sm-6 col-md-6 col-lg-6 bg-danger">
            <h3>第一行第二列</h3>
        </div>
    </div>
    <div class="row">
        <div class="col-xs-5 col-sm-5 col-md-5 col-lg-5 bg-warning">
            <h3>第二行第一列</h3>
        </div>
        <div class="col-xs-5 col-sm-5 col-md-5 col-lg-5 bg-success">
            <div class="row">
                <div class="col-xs-5 col-sm-5 col-md-5 col-lg-5 bg-success">
                    <h3>第二行第一列</h3>
                </div>
                <div class="col-xs-5 col-sm-5 col-md-5 col-lg-5 bg-success">
                    <h3>第二行第2列</h3>
                </div>
            </div>
        </div>
    </div>
</div>
</body>
</html>